How do I write this? Talking in MC's head.

A bit of editing aside, the general format looks good to me. You could also use quotation marks instead of italics, but italics has lately become the more common way to show internal dialogue.

You're on the right track. You can even craft internal dialogue (voices) in much the same way . . .


Midway down the dark basement stairs, she froze.

What was that? I heard something!

No, you didn't - it's just your imagination!

Oh, why didn't I bring the flashlight?

Because you left it in the car - now, get a grip!

No way! I'm outta here!

Spinning around, she fled up the stairs.

Unh-uh, I've seen this movie - my momma didn't raise no dummies!

I would capitalize "too":

Whispers, like a buzzing in my ear, repeat, Too pale, too pale.

and in fact punctuate all your italicized "speech" as if it's regular dialog without the quote marks.

This is a very cool idea. I've never done this before. I like the quotation marks, but I also like the stream of conscious-type idea. Let it flow.

Neat-O! = D

Italics have become more common, perhaps to the point where speech marks associated with thoughts might even become confusing or jolting.
The you used style works for me. I might separate "It’s no use they never listen." into two sentences and have a paragraph break beforehand, but that's for different consideration...
I'm not sure if some might recommend using a colon before "too pale, too pale" if the transition seems awkward to others without the speech marks. Maybe somebody else could weigh in on suitability of that option. Alternatively:
Whispers echo inside my ear. Too pale, too pale.